Update libgit2 to 0.19.0

[ben]

🚧👷 WIP DO NOT MERGE 👷🚧

Libgit2 recently released v0.19.0, and there are a number of improvements that node-gitteh could take advantage of (see #8).

However, there are also a number of API changes that need to be adjusted for. In some cases this will probably mean changing the gitteh API as well.

A quick summary:

• The GIT_DIR_* macros were changed into an enum, and their names changed.
• git_indexer_stats is now called git_transfer_progress, and its fields have changed names and semantics.
  • This needs review, see fe575ad
• All the calls that ended with _oid now end with _id
• Callbacks passed to git_submodule_foreach now take a git_submodule* as a parameter. We may be able to do better inside Repository::SubmoduleListCallback with this, but for now I've just added the parameter to the signature.
• Push and fetch refspecs are now arrays, which affects the way we create remotes.
  • This needs review, see 7c3646e
• Once the C++ compiles, the JS API surface will have to change to match.

[ben]

Opening this early so I can get some feedback. I've done most of the work to get gitteh compiling again, but I haven't actually been able to run the tests yet, so none of the api changes have made it into the coffeescript source.

[mildsunrise]

👍 Great work!

Hey, what about the -fPIC flag issue we discussed earlier (0.18 doesn't
add the flag when producing static lib, which causes build to fail in x64 systems).

And since 0.19 inherits this behaviour, we should manually add the flag.

[ben]

@jmendeth, this forces cmake to include the -fPIC flag when building. We might have to revise that when we do Windows support, but this should fix it for now.

[mildsunrise]

Ok, that will do it for now.

[ben]

Travis is 💚! I'd like some more eyes on the changes to refspecs and progress notifications, but otherwise I think this is good to go.

[samcday]

@ben Just reviewed and it all looks rather sexcellent actually. Awesome work!

I'm a little confused though - I tried running the tests locally and I'm getting a few fails. Also the merge commit that Travis built (dd6d82e) I can't even find in my local repo, though I can see the HEAD of this PR (a3e10bb)... O.o

[samcday]

Oh jesus I forgot to run cake build... Coffee hasn't kicked in yet.

[samcday]

@ben as you said there's some issues with the JS api now (particularly around the refspec changes), and these unfortunately aren't being picked up by the tests (possibly because there is none yet for remotes ... derp).

I'm going to merge this in now and fix up the JS API.

[ben]

Good point – I was just making sure the tests passed, I didn't try to fix up anything that wasn't covered by them. 😊

[samcday]

Haha yeah it's totoally my bad not having better coverage. I'm going to rectify that as I update the broken parts of the API ;)

[iamwilhelm]

quick question: how different is 0.19's API from 0.17? I'm still in the middle of upgrading to 0.17, and if it's significantly different, I might as well just move all the way to 0.19

[ben]

Pretty different. Here's the quick bullet list from 0.18.0:

• major improvements to API consistency
• fetch and push over several protocols (including native WinHTTP support)
• new/improved APIs for branch management, clone, checkout, notes, pack building, remotes, revparse (for both single and commit ranges), reset, stash, submodules
• custom backend support for objects (odb) and references (refdb)
• beautifully reworked clar testing framework and more than 600 new tests
• diff rename detection, typechange and submodule support, and iteration APIs
• builds for MinGW, OpenBSD, FreeBSD, Android, Solaris, AmigaOS, et al. on top of 32-bit and 64-bit Windows, MacOS, and Linux

And here's the list for v0.19.0:

• New (threadsafe) cache for objects
• Iterator for Status
• New Merge APIs
• SSH support on *NIX
• Function context on diff
• Namespaces support
• Index add/update/remove with wildcard support
• Iterator for References
• Fetch and push refspecs for Remotes
• Rename support in Status
• New 'sys/` namespace for external headers with low-level APIs

And a quick function-level changelist. We're trying to get all of the breaking changes done before marking a 1.0 release, so lots of stuff has happened.

[iamwilhelm]

Thanks for the info. I should have been a little clearer with my question, since the version numbers for gitteh are close to the version numbers for libgit2. Will the API for gitteh change significantly from 0.17 to 0.19?

[samcday]

@iamwilhelm it will change, as is expected when the major version component is still 0.

That said however, the API for gitteh is pretty far removed from libgit2 itself, so things like naming changes won't affect Gitteh API so much, and added features will generally not cause existing API changes either.

That said the move to gitteh version 0.17.0 is significant as it was a complete refactor, so if you move up to 0.17 now you won't have many problems moving up to 0.19.0 when it's available.